Handle design for a medical catheter

ABSTRACT

A handle for use with a catheter, the handle including a housing, a cable, and a guide. The housing has a proximal end, a distal end, and a longitudinal axis that extends from the proximal end of the housing to the distal end of the housing. The cable is disposed in the housing and extends through the proximal end of the housing. A portion of the cable that is disposed in the housing is movable, under compression, in a first direction that is substantially aligned with the longitudinal axis of the housing. The guide is disposed in the housing and is adapted to prevent the portion of the cable from moving in a second direction that is transverse to the first direction when the portion of the cable is moved in the first direction. The handle is suitable for use with an electrophysiology catheter having an elongated shaft.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application Ser.No. 60/287,057, entitled “Handles For Medical Devices,” filed Apr. 27,2001, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to handles for use with catheters, andmore particularly to handles for use with electrophysiology cathetersthat are used in performing endocardial mapping and/or ablationprocedures.

2. Discussion of the Related Art

The human heart is a very complex organ, which relies on both musclecontraction and electrical impulses to function properly. The electricalimpulses travel through the heart walls, first through the atria andthen the ventricles, causing the corresponding muscle tissue in theatria and ventricles to contract. Thus, the atria contract first,followed by the ventricles. This order is essential for properfunctioning of the heart.

In some individuals, the electrical impulses of the heart develop anirregular propagation, disrupting the heart's normal pumping action. Theabnormal heartbeat rhythm is termed a “cardiac arrhythmia.” Arrhythmiasmay occur when a site other than the sinoatrial node of the heart isinitiating rhythms (i.e., a focal arrhythmia), or when electricalsignals of the heart circulate repetitively in a closed circuit (i.e., areentrant arrhythmia).

Techniques have been developed which are used to locate cardiac regionsresponsible for the cardiac arrhythmia, and also to disable the shortcircuit function of these areas. According to these techniques,electrical energy is applied to a portion of the heart tissue to ablatethat tissue and produce scars which interrupt the reentrant conductionpathways or terminate the focal initiation. The regions to be ablatedare usually first determined by endocardial mapping techniques. Mappingtypically involves percutaneously introducing a catheter having one ormore electrodes into the patient, passing the catheter through a bloodvessel and into an endocardial site, and deliberately inducing anarrhythmia so that a continuous, simultaneous recording can be made witha multichannel recorder at each of several different endocardialpositions. When an arrythormogenic focus or inappropriate circuit islocated, as indicated in the electrocardiogram recording, it is markedby various imaging or localization means so that cardiac arrhythmiasemanating from that region can be blocked by ablating tissue. Anablation catheter with one or more electrodes can then transmitelectrical energy to the tissue adjacent the electrode to create alesion in the tissue. One or more suitably positioned lesions willtypically create a region of necrotic tissue which serves to disable thepropagation of the errant impulse caused by the arrythromogenic focus.Ablation is carried out by applying energy to the catheter electrodes.The ablation energy can be, for example, RF, DC, ultrasound, microwave,or laser radiation.

Atrial fibrillation together with atrial flutter are the most commonsustained arrhythmias found in clinical practice.

Current understanding is that atrial fibrillation is frequentlyinitiated by a focal trigger from the orifice of or within one of thepulmonary veins. Though mapping and ablation of these triggers appearsto be curative in patients with paroxysmal atrial fibrillation, thereare a number of limitations to ablating focal triggers via mapping andablating the earliest site of activation with a “point” radiofrequencylesion. One way to circumvent these limitations is to determineprecisely the point of earliest activation. Once the point of earliestactivation is identified, a lesion can be generated to electricallyisolate the trigger with a lesion; firing from within those veins wouldthen be eliminated or unable to reach the body of the atrium, and thuscould not trigger atrial fibrillation.

Another method to treat focal arrhythmias is to create a continuous,annular lesion around the ostia (i.e., the openings) of either the veinsor the arteries leading to or from the atria thus “corralling” thesignals emanating from any points distal to the annular lesion.Conventional techniques include applying multiple point sources aroundthe ostia in an effort to create such a continuous lesion. Such atechnique is relatively involved, and requires significant skill andattention from the clinician performing the procedures.

Another source of arrhythmias may be from reentrant circuits in themyocardium itself. Such circuits may not necessarily be associated withvessel ostia, but may be interrupted by means of ablating tissue eitherwithin the circuit or circumscribing the region of the circuit. Itshould be noted that a complete ‘fence’ around a circuit or tissueregion is not always required in order to block the propagation of thearrhythmia; in many cases simply increasing the propagation path lengthfor a signal may be sufficient. Conventional means for establishing suchlesion ‘fences’ include a multiplicity of point-by-point lesions,dragging a single electrode across tissue while delivering energy, orcreating an enormous lesion intended to inactivate a substantive volumeof myocardial tissue.

SUMMARY OF THE INVENTION

The present invention encompasses handles that may be used with acatheter, and more particularly with an electrophysiology catheter formapping electrical activity within the heart. The present invention alsoencompasses handles that may be used with an electrophysiology catheterto create lesions in the heart tissue (ablating), thereby creating aregion of necrotic tissue which serves to disable the propagation oferrant electrical impulses caused by an arrhythmia.

According to one aspect of the present invention, a handle for use witha catheter is provided. The handle comprises a housing, a cable, and aguide. The housing has a proximal end, a distal end, and a longitudinalaxis that extends from the proximal end of the housing to the distal endof the housing. The cable is disposed in the housing and extends throughthe proximal end of the housing. A portion of the cable that is disposedin the housing is movable, under compression, in a first direction thatis substantially aligned with the longitudinal axis of the housing. Theguide is disposed in the housing and is adapted to prevent the portionof the cable from moving in a second direction that is transverse to thefirst direction when the portion of the cable is moved in the firstdirection.

According to another aspect of the present invention, a handle for usewith a catheter is provided. The handle comprises a housing having aproximal end, a distal end, and a longitudinal axis that extends fromthe proximal end of the housing to the distal end of the housing, and acable, disposed in the housing, that extends through the proximal end ofthe housing. A portion of the cable that is disposed in the housing ismovable, under compression, in a first direction that is substantiallyaligned with the longitudinal axis of the housing. The handle furthercomprises means for preventing the portion of the cable from moving in asecond direction that is transverse to the first direction when theportion of the cable is moved in the first direction.

According to a further aspect of the present invention, a method ofusing a catheter having a handle is provided. The handle has a proximalend, a distal end, and a longitudinal axis that extends from theproximal end of the handle to the distal end of the handle. The methodcomprises acts of applying a compressive force to a portion of a cablethat is disposed in the handle to move the portion of the cable in afirst direction that is substantially aligned with the longitudinal axisof the handle, and preventing the portion of the cable from moving in asecond direction that is transverse to the first direction in responseto the act of applying.

According to another aspect of the present invention, a handle for usewith a catheter having an elongated shaft is provided. The handleincludes a housing, a cable, and an actuator. The handle has a proximalend and a distal end, the distal end of the housing being attached to aproximal end of the elongated shaft. The cable is disposed in thehousing and extends through the distal end of the housing and into theelongated shaft. The actuator is attached to the housing and the cable,and is movable between a first position in which the cable extends afirst distance into the elongated shaft and a second position in whichthe cable extends a second distance into the elongated shaft, the seconddistance being less than the first distance. The handle further includesa guide, disposed in the housing, that is adapted to maintain a portionof the cable that is disposed between the distal end of the housing andthe actuator when the actuator is in the second position in asubstantially fixed lateral position when the actuator is moved towardthe first position.

According to a further aspect of the present invention, a handle for usewith a catheter having an elongated shaft is provided. The handleincludes a housing, a cable, and an actuator. The handle has a proximalend and a distal end, the distal end of the housing being attached to aproximal end of the elongated shaft. The cable is disposed in thehousing and extends through the distal end of the housing and into theelongated shaft. The actuator is attached to the housing and the cable,and is movable between a first position in which the cable extends afirst distance into the elongated shaft and a second position in whichthe cable extends a second distance into the elongated shaft, the seconddistance being less than the first distance. The handle further includesguide means, disposed in the housing, for maintaining a portion of thecable that is disposed between the distal end of the housing and theactuator when the actuator is in the second position in a substantiallyfixed lateral position when the actuator is moved toward the firstposition.

According to yet another aspect of the present invention, a method foruse with a catheter having an elongated shaft and a handle is provided.The handle includes a housing having a proximal end that is attached toa proximal end of the elongated shaft, a cable that is disposed in thehousing and extends through the distal end of the housing and into theelongated shaft, and an actuator that is attached to the housing and thecable. The method comprises steps of moving the actuator from a firstposition in which the cable extends a first distance into the elongatedshaft to a second position in which the cable extends a second distanceinto the elongated shaft, the second distance being greater than thefirst distance, and maintaining a portion of the cable that is disposedbetween the distal end of the housing and the actuator when the actuatoris in the first position in a substantially fixed lateral position asthe actuator is moved toward the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative, non-limiting embodiments of the present invention aredescribed by way of example with reference to the accompanying drawings,in which:

FIG. 1 illustrates a schematic view of a mapping and/or ablationcatheter system in accordance with the present invention;

FIG. 2 is an exposed side view of a handle for a mapping and/or ablationcatheter according to one embodiment of the present invention;

FIG. 3 is an exposed top view of a section of the handle of FIG. 2 takenalong line 3-3 in FIG. 2;

FIG. 4 is an exploded view of the handle of FIG. 2;

FIG. 5 is an exposed side view of a handle for a mapping and/or ablationcatheter according to another embodiment of the present invention;

FIG. 6 is an exposed-top view of a section of the handle of FIG. 5 takenalong line 6-6 in FIG. 5 according to one embodiment of the presentinvention;

FIG. 7 is an exposed top view of a section of the handle of FIG. 5 takenalong line 7-7 in FIG. 5 according to another embodiment of the presentinvention;

FIG. 8 is a top view of a thumb wheel actuator according to anembodiment of the present invention;

FIG. 9 is an elevational view of the thumb wheel actuator of FIG. 8;

FIG. 10 is a side view of the thumb wheel actuator of FIG. 8;

FIG. 11 is a perspective view of a distal end tip assembly that may beused with the catheter system of FIG. 1, and which includes a slidingelectrode;

FIG. 12 is a cross sectional side view of the distal end tip assembly ofFIG. 11 taken along line 12-12 in FIG. 11;

FIG. 13 is a cross sectional end view of the distal end of tip assemblyof FIG. 11 taken along line 13-13 in FIG. 12;

FIG. 14 is a perspective view of a distal end of the catheter thatincludes a braided conductive mesh that may be radially expanded andcollapsed about the circumference of the shaft of the catheter;

FIG. 15 is a side view of the distal end of the catheter illustrated inFIG. 14, showing the braided conductive mesh in a collapsed state; and

FIG. 16 is an elevational view of another handle that may be used withthe catheter system of FIG. 1 according to another embodiment of theinvention that includes a third actuator.

DETAILED DESCRIPTION

In the follow description, the invention will be explained withparticular reference to an electrophysiology catheter. However, thepresent invention is not so limited, and may be applied to any devicewhere control of lateral cable movement is advantageous.

System Overview

Reference is now made to FIG. 1, which illustrates an overview of amapping and/or ablation catheter system for use in electrophysiologyprocedures, in accordance with one embodiment of the present invention.The system includes a catheter 100 having a flexible shaft 110, acontrol handle 120, and a connector 130. When used in mappingapplications, the connector 130 is used to allow signal wires runningfrom one or more mapping electrodes at a distal end of the catheter 100to be connected to a device for recording signals, such as a recordingdevice 160. When used in ablation applications, connector 130 is used toallow signal wires running from ablation electrodes at the distal end ofthe catheter 100 to be connected to a device for generating ablationenergy, such as ablation energy generator 170.

A controller 150 is electrically connected to connector 130 via cable115. In one embodiment, controller 150 may be a QUADRAPULSE RFCONTROLLER™ device available from C.R. Bard, Inc., Murray Hill, N.J.Ablation energy generator 170 may be connected to controller 150 viacable 116. Recording device 160 may be connected to controller 150 viacable 117. When used in an ablation application, controller 150 is usedto control ablation energy, provided by ablation energy generator 170,to catheter 100. When used in a mapping application, controller 150 isused to process signals from catheter 100 and provide these signals torecording device 160. Although illustrated as separate devices,recording device 160, ablation energy generator 170, and controller 150may be incorporated into a single device. It should further beappreciated that although both ablation energy generator 170 andrecording device 160 are illustrated in FIG. 1, either or both of thesedevices may be incorporated in the catheter system in accordance withthe present invention.

In this description, various aspects and features of the presentinvention will be described. The various aspects and features arediscussed separately for clarity. One skilled in the art will appreciatethat the features may be selectively combined in a device depending onthe particular application. Furthermore, any of the various features maybe incorporated in a catheter and associated method of use for mappingand/or ablation procedures.

Catheter Overview

As noted above, electrophysiology catheters such as the catheter 100illustrated in FIG. 1 generally include a flexible shaft 110, a controlhandle 120, and a connector 130. The distal end 140 of the catheter 100generally includes one or more electrodes 146 a, 146 b that may be usedfor mapping and/or ablation. The electrodes 146 a, 146 b are typicallyconnected to signal wires extending along a length of the shaft 110,which are, in turn electrically connected to connector 130.

Frequently, one or more pull wires are also attached to a distal end 140of the catheter 100 to control the distal end 140 of the catheter 100.The pull wires extend from the distal end 140 of the catheter along thelength of the shaft 110 with the proximal end of the pull wirestypically being attached to one or more actuators 122, 124 that aredisposed on the handle 120. The actuators 122, 124 may be used for avariety of purposes, such as steering of the distal end 140 of thecatheter 100 in one or more directions, controlling movement of amovable element (e.g., a movable electrode or a movable braidedconductive mesh) disposed on the distal end 140 of the catheter 100,adjusting a radius of curvature of a distal end 140 of the catheter 100,etc.

For example, U.S. Pat. Nos. 5,383,852, 5,462,527, and 5,611,777hereinafter referred to as the '852, '527, and '777 patents), which areincorporated herein by reference, illustrate various embodiments of acontrol handle that may be used for steering an electrophysiologycatheter. Commonly assigned and co-pending PCT application entitledELECTROPHYSIOLOGY CATHETER FOR MAPPING AND/OR ABLATION, filed Mar. 29,2002 (hereinafter referred to as the PCT application), which isincorporated herein by reference, illustrates various embodiments of acontrol handle that may be used for adjusting a radius of curvature ofan arcuately curved distal tip portion of the catheter, for moving amovable electrode along a length of the arcuately curved distal tipportion of the catheter, for controlling steering of the arcuatelycurved distal tip portion of the catheter, and for actively bending thearcuately curved distal tip portion of the distal end of the catheter sothat the arcuate curve is oriented in a plane that is approximatelyperpendicular to a longitudinal axis (L1 of FIG. 1) of the shaft of thecatheter. Moreover, co-pending and commonly assigned U.S. patentapplication Ser. No. 09/845,022, entitled APPARATUS AND METHODS FORMAPPING AND ABLATION IN ELECTROPHYSIOLOGY PROCEDURES, filed Apr. 27,2001 (hereinafter referred to as the co-pending application), which isincorporated herein by reference, illustrates various embodiments of acontrol handle that may be used to deploy (i.e., radially expand) andun-deploy (i.e., collapse) a braided conductive mesh that is disposed atthe distal end of the catheter.

In each of the above noted catheters, the wires that are used to controlthe distal end of the catheter are typically operable under tension(hence the term ‘pull wire’), such that tension applied to the pull wireby movement of an actuator disposed on the handle results in movement ofthe distal end of the catheter, or movement of a movable elementdisposed on the distal end of the catheter. Frequently, the pull wiresare associated in pairs, such that one pull wire of a pair controlsmovement of the distal end of the catheter (or movement of a movableelement disposed on the distal end of the catheter) in a firstdirection, and the other pull wire of the pair controls movement of thedistal end of the catheter (or movement of a movable element disposed onthe distal end of the catheter) in a second direction, frequentlyopposite to the first direction. In general, except for when theactuator is in a neutral position, one pull cable of the pair of pullcables is in tension, and the other pull cable of the pair is not (i.e.,is slack).

The Handle

Handles in accordance with the present invention are shown in FIGS. 2-7.In each of the illustrated embodiments, the handle includes a guide thatpermits a small diameter cable, for example only 0.011 inches indiameter, to be used in both tension and in compression. The guide actsto maintain a portion of the cable that is disposed within the handle ina substantially fixed lateral position within the handle as the cable isurged distally toward the proximal end of the shaft. The term“substantially fixed lateral position” is defined herein to mean thatthe portion of the cable that is disposed within the handle is preventedfrom moving, bending, or bowing in a direction transverse to the desireddirection of movement of the cable. By maintaining the portion of thecable in a substantially fixed lateral position, the column strength ofthe cable is increased such that a compressive force applied to thecable by movement of an actuator attached to the cable is translatedinto distal movement of the cable. The distal movement of cable may beused for a myriad of different uses, as indicated above.

In the embodiment of FIGS. 2, 3, and 4, linear movement of a slideactuator 124 (FIG. 1) is used to move a portion of a cable that isdisposed in the handle distally into and proximally out of the shaft 110of the catheter 100. In the embodiment of FIGS. 5 and 6, rotary movementof a thumb wheel actuator 122 (FIG. 1) is used to move a portion of acable that is disposed in the handle distally into and proximally out ofthe shaft 110 of the catheter 100, and in the embodiment of FIG. 7,rotary movement of the thumb wheel actuator 122 is used to moverespective portions of two different cables that are disposed in thehandle distally into and proximally out of the shaft 110 of the catheter100. Advantageously, in each of these embodiments, a single cable mayused in both tension and compression. Although not limited to anyspecific use, the single cable may be used to control steering of thedistal end 140 of the catheter 100, to control movement of a movableelement (e.g., a movable electrode or a movable braided conductive mesh)disposed on the distal end 140 of the catheter 100, to adjust a radiusof curvature of an arcuately curved distal tip portion of the catheter,to control bending of an arcuately curved distal tip portion of thedistal end of the catheter so that the arcuately curved distal tipportion is oriented in a plane that is approximately perpendicular to alongitudinal axis of the shaft of the catheter, etc.

Referring to FIGS. 2-4, a handle according to a first embodiment of thepresent invention is described. The handle 120 comprises a housinghaving a left section 200L and a right section 200R. These two sections200L and 200R are somewhat semicircular in cross section and have flatconnecting surfaces which may be secured to each other, for example, byscrews 202, along a common plane to form a complete housing for thehandle 120. The outer surfaces of the handle 120 are contoured to becomfortably held by the user.

A wheel cavity 204 is formed within the right section 200R of the handle120.

The wheel cavity 204 includes a planar rear surface 206 which isgenerally parallel to the flat connecting surface of the handle 120. Thethumb wheel actuator 122 is a generally circular disc having a centralbore 208, an integrally formed pulley 210, and upper and lower cableanchors 212. Upper and lower cable guides 214 serve to retain pullcables 216 a and 216 b within a guide slot or groove 218 formed in asurface of the integrally formed pulley 210. The pull cables 216 a and216 b may be used for a variety of purposes, such as for steering of thedistal end of the catheter. For example, as described in the '852, '527,and '777 patents, the distal ends of the pull cables 216 a, 216 b mayextend through the shaft 110 and be connected to the distal end 140 ofthe catheter at an off-axis location, whereby tension applied to one ormore of the pull wires causes the distal portion of the catheter tocurve in a predetermined direction or directions.

In the embodiment illustrated, the thumb wheel 122 rotates about asleeve 220 inserted in the central bore 208. The thumb wheel 122 is heldin position by a shoulder nut 222 that mates with a threaded insert 224in the planar rear surface 206 of the right section 200R of the handle120. To provide friction that permits the thumb wheel to maintain itsposition even when tension is applied to one of the cables 216 a, 216 b,a friction disk 226 is provided between the shoulder nut 222 and thethumb wheel 122. Tightening of the shoulder nut 222 increases the amountof friction applied to the thumb wheel 122.

A peripheral edge surface 228 of the thumb wheel 122 protrudes from awheel access opening so that the thumb wheel 122 may be rotated by thethumb of the operator's hand which is used to grip the handle 120. Toensure a positive grip between the thumb wheel 122 and the user's thumb,the peripheral edge surface 228 of the thumb wheel 122 is preferablyserrated, or otherwise roughened. Different serrations on oppositehalves of thumb wheel 122 enable the user to “feel” the position of thethumb wheel.

The left section 200L of the handle 120 supports part of the mechanismfor applying tensile and compressive forces to the cable 230. As will bedescribed in detail further below, tensile and compressive force may beapplied to cable 230 via the slide actuator 122 (FIG. 1) to move theportion of the cable 230 that is disposed within the handle proximallyand distally within the handle 120. Where a distal end of the cable 230is attached to a distal end of the catheter, movement of the slideactuator proximally and distally along the handle may be used to steerthe catheter, or to control a radius of curvature of an arcuately curvedtip assembly that is attached to the distal end of the catheter asdescribed in the aforementioned PCT application. Alternatively, movementof the slide actuator proximally and distally along the handle may beused to actively bend a tip assembly this is attached to a distal end ofthe catheter so as to orient an arcuately curved portion of the tipassembly in a plane that is approximately perpendicular to alongitudinal axis of the shaft and then return the arcuately curvedportion of the tip assembly to its original orientation. Alternativelystill, where the distal end of the cable is attached to a movableelement that disposed on the distal end of the catheter, movement of theslide actuator proximally and distally may be used to move the movableelement proximally and distally along a length of the distal end of thecatheter.

To accommodate the protruding portion of the thumb wheel 122, the lefthandle section 200L includes a wheel access opening similar in shape tothe wheel access opening of the right handle section 200R. It alsoincludes an elongated slot 232 in its side surface. A slider 234 isprovided with a neck portion 236 which fits snugly within the slot 232.The slider 234 includes a bore 238 to receive a proximal end of thecable 230. The proximal end of the cable 230 is inserted into the bore238 and held in place by a set screw 240. The proximal end of the cablemay additionally or alternatively be secured within the bore 238 usingan epoxy.

According to the embodiment illustrated in FIG. 4 in which cable 230 isused to conduct electrical signals from the distal end of the catheter(e.g., to conduct electrical signals from a movable electrode or abraided conductive mesh), the electrically insulating coating of thecable 230 is removed prior to inserting the cable into the bore 238 ofthe slider. In this embodiment, a signal wire 242 is soldered to thestripped proximal end of the cable 230 and the soldered electricalconnection is covered by an insulating shield or cover 244. Theinsulating shield or cover 244 reduces electrical interference andprevents short circuiting with any other signal wires. A secondinsulating shield or cover 246 is placed about signal wire 242 andsecured in place, for example with expoxy 248 in a proximal portion ofthe right section of the handle 200R. Although the second insulatingcover 248 is epoxied in place, the signal wire 242 is pennitted to moveproximally and distally within the second insulating cover 248. Theproximal end of signal wire 242 may be electrically connected to theconnector 130 (FIG. 1). Further, a sufficient amount of excess wile isprovided to allow for such movement of the signal wire 242. It should beappreciated that the cable 230 may alternatively extend to the connector130, such that the signature 242 is omitted.

A slider grip 250 is attached to the neck portion 236 of the slider 234and positioned externally of the handle 120. The slider grip 250 ispreferably ergonomically shaped to be comfortably controlled by theuser. Together, the slider 234 and the slider grip 250 form the slideactuator 124 depicted in FIG. 1. Preload pads 252 are positioned betweenthe outer surface of the left handle section 200L and the slider grip250. By tightening the screws 256 that attach the slider grip 250 to theslider 234, friction may be applied to the slider 234 and thus, to thecable 230. Preload pads 254 may also be placed on a surface of theslider 234 for a similar purpose.

A dust seal 258 having an elongated slit and preferably made from latexis bonded along the slot 232 within the left handle section 200L. Theneck portion 236 of the slider 234 protrudes through the slit of thedust seal 258 so that the slit only separates adjacent to the neckportion 236. Otherwise, the slit remains “closed” and functions as aneffective barrier preventing dust, hair and other contaminants fromentering the handle 120. Additional details of the handle 120 aredescribed in '852, '527, and '777 patents, as well as in the PCTapplication and the co-pending application.

According to an embodiment of the present invention, a cable guide 260is attached to the right handle section 200R and used to maintain theportion of the cable 230 that is disposed within the handle 120 in asubstantially fixed lateral position within the handle as the slider 124is moved distally and proximally along the handle 120. In theillustrated embodiment, this substantially fixed lateral position isgenerally aligned with a longitudinal axis (L2) in FIG. 1 of the handle120 and the proximal end of the shaft 110. In the illustratedembodiment, the guide 260 includes a cylindrical mandrel 262 and aretainer 264, although it should be appreciated that the guide may beintegrally formed within the left and right handle sections 200L and200R. As illustrated, the retainer 264 includes a bore to receive themandrel 262 and may also include a slot 266 to guide the cables 216 a,216 b that are attached to the thumb wheel 122 and prevent theirentanglement with one another.

The mandrel 262 may be formed from any suitable material, for example,from stainless steel hypodermic tubing, that is sufficiently stiff toprevent the cable from bowing in a direction that is orthogonal (i.e.,lateral) to a longitudinal axis (22) of the handle 120. The mandrel 262has an inner diameter that is slightly greater than an outer diameter ofthe cable 230, and has a length that is approximately twenty percent ormore than a length of the portion of the cable that is disposed withinthe handle when the slider 234 is in its most proximal position. Itshould be appreciated that the mandrel need not be cylindrical in shape,as other shapes may be used, so long as they are capable of preventingmovement of the cable 230 in a lateral direction.

It should be appreciated that the length of the mandrel 262 may varydepending upon the dimensions of the handle 120 and the desired amountof movement of the cable 230 proximally and distally within the handle120. In general, the mandrel 262 should be sufficiently long to preventthe cable 230 from bending in a direction that is transverse (i.e.,lateral) to the desired direction of movement of the cable 230 as acompressive force is imparted to the cable 230 via the slide actuator124. As shown, the mandrel 262 is positioned within the retainer so thatthe portion of the mandrel 262 that is distal of the retainer 264 islonger than the portion that is proximal of the retainer 264. Thispermits the slider 234 to have a sufficient amount of travel (e.g.,approximately one inch) between its farthest proximal and distalpositions.

Where the mandrel 262 is formed from a straight cylindrical member, andthe portion of the cable 230 that is fixed in position within the slider234 is not aligned with the longitudinal axis of the proximal end of theshaft (for example, is at a different elevation than the proximal end ofthe shaft), the mandrel 262 should preferably terminate prior to theproximal end of the shaft 110 to permit the cable 230 to bend slightlyprior to entering the proximal end of the shaft. Where the portion ofthe cable 230 that is fixed in position within the slider 234 is alignedwith the longitudinal axis of the proximal end of the shaft 110, orwhere the mandrel 262 is shaped so as to guide the cable 230 into theproximal end of the shaft 110 along the longitudinal axis of theproximal end of the shaft, the mandrel 262 may terminate just distallyof the proximal end of the shaft 110.

In one embodiment, the cylindrical mandrel has an inner diameter ofapproximately 0.025-0.030 inches, and a length of approximately ¾^(th)of an inch. In this embodiment, the portion of the mandrel 262 that isdisposed distally of the retainer 264 is approximately 0.5 inches inlength. Applicant has found that the above dimensions permit a stainlesssteel cable 230 having an outer diameter of approximately 0.020 inchesto be used with the catheter 100 while imparting a sufficient columnstrength to the cable 230 to permit it to drive the cable 230 incompression distally along a length of the shaft 110. The cable 230 ispreferably ground to have an outer diameter of approximately ofapproximately 0.011 inches just prior to where it enters the shaft 110of the catheter 100, to reduce the overall outer diameter of thecatheter shaft 110. Despite the reduced diameter of the cable 230 thatis within the shaft 110 of the catheter 100, the outer casing of thecatheter shaft prevents movement of the cable in a direction other thandistally along the length of the shaft 110. It should be appreciatedthat the very distal end of the cable 230 may also be ground to an evensmaller outer diameter to further reduce the overall outer diameter ofthe distal end 140 of the catheter 100.

In another embodiment, the cylindrical mandrel has an inner diameter ofapproximately 0.055-0.060 inches, a length of approximately ¾^(th) of aninch, and the length of the portion of the mandrel 262 that is disposeddistally of the retainer 264 is again approximately 0.5 inches inlength. In this embodiment, a stainless steel cable 230 having an outerdiameter of approximately 0.050 inches is used, with the outer diameterof the cable 230 being ground to approximately 0.020 inches where thecable 230 enters the catheter shaft 110, and being ground to an outerdiameter of approximately 0.011 inches at the distal end 140 of thecatheter. It should be appreciated that other dimensions for the variousportions of the cable 230 may alternatively be used, depending upon theintended application.

It should also be appreciated that, rather than grounding cable 230 tovarying diameters, a small diameter (e.g., 0.050 inches or less in outerdiameter) piece of hypodermic tubing may alternatively be used. Forexample, rather than having the cable 230 extend all the way to theslide actuator 122, the proximal end of the cable 230 may be solderedwithin a small diameter piece of hypodermic tubing just prior to wherethe cable 230 enters the shaft 110 of the catheter, with the hypodermictubing then being attached to the slide actuator 122. This alternativemanner of construction avoids the grinding of a significant length ofthe cable 230 that may be desired to reduce the overall outer diameterof the shaft 110 of the catheter. Any grinding that was desired to bedone to the distal end of the cable 230 to further the outer diameter ofthe distal end 140 of the catheter would then be limited to the relativesmall length of the distal end of the cable 230.

Alternatively still, rather than the proximal end of the cable 230terminating just prior to where the cable 230 enters the shaft 110, andbeing soldered or otherwise affixed to a distal end of the hypodermictubing, the cable 230 may extend to and past the slide actuator. Thehypodermic tubing could then be soldered in position around the portionof the cable that is within the handle, to prevent that portion of thecable 230 from moving in a transverse direction under compression. Theslider may then be attached to both the hypodermic tubing and the cable230 which is soldered or otherwise fixed (e.g., by an epoxy) therein.Other suitable types of construction will of course be appreciated bythose skilled in the art, as the present invention is not limited to aparticular construction of the cable 230.

FIGS. 5 and 6 illustrate alternative embodiments of the presentinvention in which rotary movement of a thumb wheel actuator 122(FIG. 1) is used to move a portion of a cable that is disposed in thehandle 120 distally into and proximally out of the shaft 110 of thecatheter 100, and FIG. 7 illustrates yet another alternative embodimentin which rotary movement of the thumb wheel actuator 122 is used to moverespective portions of two different cables that are disposed in thehandle 120 distally into and proximally out of the shaft 110 of thecatheter 100. As each of the handles illustrated in FIGS. 5, 6, and 7share many of the same elements as the handle described with respect toFIGS. 2, 3, and 4, only those elements that differ from the embodimentof FIGS. 2, 3, and 4 are described in detail herein.

In the embodiments illustrated in FIGS. 5, 6, and 7, rather thansecuring a single cable 230 that is used in both tension andcompression, the slider 234 includes a forward cable anchor 535 and arear cable anchor 537 for anchoring respective pull cables 516 a and 516b. Pull cable 516 b is directly attached to a forward cable anchor 535on the slider 234 and becomes taught when the slider 234 is moved towardthe distal end of the handle 120. Pull cable 516 a is guided by a returnpulley 505 prior to being attached to a rear cable anchor 537 on theslider 234 and becomes taught when the slider 234 is moved toward theproximal end of the handle 120. The return pulley 505 is rotatablyattached to a pulley axle (not shown) which is supported in the righthandle section 200R. The return pulley 505 may include a groove (notshown) to guide pull cable 516 a. The pull cable 516 a and 516 b may beused for a variety of purposes, for example, steering the distal end ofthe catheter. Further details of the construction and operation of theslider 234 are described in the '852, '527, and '777 patents, as well asthe PCT application.

In the embodiment depicted in FIGS. 5 and 6, the cable guide 260 isagain attached to the right handle section 200R. However, in theembodiment depicted in FIGS. 5 and 6, the cable guide 260 is used tomaintain the portion of a cable 516 c that is disposed within the handle120 and attached to the thumb wheel 122 in a substantially fixed lateralposition as the thumb wheel 122 is rotated clockwise and counterclockwise. Details of one implementation of the thumb wheel that may beused with this embodiment are described further below with reference toFIGS. 8, 9, and 10.

Rotation of the thumb wheel 122 in a clockwise direction (in FIG. 6)moves the cable 516 c in a proximal direction as tension is applied tothe cable 516 c via the thumb wheel 122, and rotation of the thumb wheel122 in a counterclockwise direction moves the cable 516 c in a distaldirection as a compressive force is applied to the cable 516 c via thethumb wheel 122. Cable guide 260 maintains the cable 516 c in asubstantially fixed lateral position within the handle as the thumbwheel is rotated. The cable 516 c may be used for a variety of purposes,for example, for steering or for moving a movable element proximally anddistally along a length of the distal end of the catheter.Advantageously, a single cable may be used in both tension andcompression. It should be appreciated that because only a single cablecan be used for movement in two different directions, a lesser number ofcables may be included in the shaft of the catheter without any loss infunctionality, thereby permitting a reduction in the outer diameter ofthe shaft of the catheter. Further, because of the increased columnstrength of the cable imparted by the guide 260, relatively smalldiameter cables may be used, permitting a further reduction in the outerdiameter of the shaft of the catheter.

In the illustrated embodiment, the guide 260 again includes acylindrical mandrel 262 and a retainer 264, although it should again beappreciated that the guide 260 may be integrally formed within the leftand right handle sections 200L and 200R. It should again be appreciatedthat the mandrel need not be cylindrical in shape, as other shapes maybe suitably employed. As in the embodiment of FIGS. 2-4, the retainer264 includes a bore to receive the mandrel 262. The retainer 264 mayalso include a slot, or apertures, or grooves to guide the cables 516 a,516 b that are attached to the slide actuator 124 and prevent theirentanglement with one another. The mandrel 262 may be formed from anysuitable material, for example, from stainless steel hypodermic tubing,that is sufficiently stiff to prevent the bending of the cable 516 c asthe thumb wheel 122 is rotated. As in the previously describedembodiment of FIGS. 2-4, the inner diameter of the mandrel 262 isslightly larger than the outer diameter of the cable 516 c.

In general, the length of the mandrel 262 depicted in FIGS. 5 and 6 maybe longer that that described above with respect to FIGS. 24, as thethumb wheel 122 is fixed in position along a length of the handle 120and not movable relative thereto, like the slide actuator 124. Moreover,it should be appreciated that the proximal end of the mandrel 262 shouldbe placed close to the position where the cable 516 c separates from theintegrally formed pulley 210 to prevent lateral bending of the cable 516c as the cable is urged distally by rotation of the thumb wheel 122. Asshown, the mandrel 262 terminates at a distance that is spaced apartfrom the proximal end of the shaft 110 to permit the cable 516 c to bendslightly prior to entering the proximal end of the shaft 110. It shouldbe appreciated that the mandrel 262 may alternatively be shaped so as toguide the cable 516 c into the proximal end of the shaft along thelongitudinal axis of the proximal end of the shaft, such that themandrel 262 may terminate just distally of the proximal end of theshaft.

The embodiment of the handle depicted in FIG. 7 is similar to theembodiment described above with respect to FIGS. 5 and 6. However, inthe embodiment depicted in FIG. 7, the cable guide 260 is used tomaintain respective portions of a pair of cables 516 c, 516 d that aredisposed within the handle 120 and attached to the thumb wheel 122 in asubstantially lateral fixed positions as the thumb wheel 122 is rotatedclockwise and counter clockwise. Each of the cables 516 c and 516 d isanchored to the thumb wheel 122 by respective cable anchor 712.

Rotation of the thumb wheel 122 in a clockwise direction (in FIG. 7)moves the cable 516 c in a proximal direction as a tensile force isapplied to the cable 516 c via the thumb wheel 122, and moves the cable516 d in a distal direction as a compressive force is applied to thecable 516 d via the thumb wheel 122. Similarly, rotation of the thumbwheel 122 in a counterclockwise direction moves the cable 516 c in adistal direction as a compressive force is applied to the cable 516 cvia the thumb wheel 122, and moves the cable 516 d in a proximaldirection as a compressive force is applied to the cable 516 d via thethumb wheel 122. The cable guide 260 again maintains each of the cables516 c and 516 d in a substantially fixed lateral position in bothtension and compression.

The cables 516 c and 516 d may be used for a myriad of purposes as notedabove, for example, for steering or for moving a movable elementproximally and distally along a length of the distal end of thecatheter. It should be appreciated that the cables 516 c and 516 d mayoperate in tandem, for example, with one cable (e.g., 516 c) controllingmovement of the distal end of the catheter in a first direction and theother cable (e.g., 516 d) controlling movement of the distal end of thecatheter in an opposite direction, or may be used to control differentfunctions.

In the embodiment illustrated in FIG. 7, the guide 260 includes a pairof mandrels 262 a, 262 b and a retainer 264. It should be appreciatedthat the mandrels 262 a, 262 b need not be cylindrical, as other shapesmay be suitably employed. As in the previously described embodiments,the guide 260 may alternatively be integrally formed within the left andright handle sections 200L and 200R, rather than separate therefrom. Theretainer 264 includes a pair of bores to receive each of the mandrels262 a, 262 b.The mandrels 262 a, 262 b may be formed from any suitablematerial, as described above with respect to FIGS. 2-6. Although notseparately depicted, it should be appreciated that the handles describedabove with respect to FIGS. 5, 6, and 7 may alternatively be used with aslide actuator 124, such as that described with respect to FIGS. 2-4.That is, the slider 232 (FIGS. 2-4) may be used to control a singlecable that is operable in both tension and compression, rather than apair of pull cables 516 a, 516 b, and the thumb wheel 122 may be used tocontrol one or a pair of cables, each of which is operable in bothtension and compression.

FIGS. 8-10 illustrate one implementation of a thumb wheel 122 that maybe used with the embodiments of the handle 120 described above withreference to FIGS. 5-7.

As previously described, the thumb wheel 122 is a generally circulardisc having a central bore 208, and an integrally formed pulley 210.However, in contrast to the thumb wheel 122 described with respect toFIGS. 2-4, surrounding a proximal portion of the pulley 210 is anarcuate wall 810. The arcuate wall 810 acts to prevent the cables 516 cand 516 d from bending away from the pulley as the thumb wheel 122 isrotated counterclockwise and clockwise, respectively. Upper and lowercable anchors 712 are disposed within the arcuate wall 810 and serve toattach the cables 516 c, 516 d to the thumb wheel 122. The arcuate wall810 spans less than 180 degrees so that rotation of the thumb wheel 122may be accomplished without the wall deflecting the cables 516 c, 516 d.For example, the thumb wheel 122 may be rotated approximately 45 degreesclockwise and approximately 45 degrees counter clockwise from a neutralposition without the wall deflecting the cables 516 d and 516 c,respectively. A top cover 820 may be attached to the thumb wheel 122 toprevent the cables 516 c, 516 d from bending in an upward direction(FIG. 10), while the surface of the thumb wheel 122 itself preventsbending of the cables in a downward direction (FIG. 10).

Distal End Configurations

As noted above, embodiments of the present invention may be used for avariety of purposes, such as, for example: steering the distal end ofthe catheter in one or more directions, adjusting a radius of curvatureof an arcuately curved distal tip portion of the catheter, moving amovable electrode along a length of the distal end of a catheter, oralong arcuately curved distal tip portion of the catheter, controllingsteering of an arcuatey curved distal tip portion of the catheter,actively bending an arcuately curved distal tip portion of the distalend of the catheter so that the arcuate curve is oriented in a planethat is approximately perpendicular to a longitudinal axis of the shaftof the catheter, or deploying and/or un-deploying a braided conductivemesh that is disposed at the distal end of the catheter.

FIGS. 11-13 illustrates a tip assembly 1100 that may be attached to adistal end of the shaft 110 of a catheter, such as the catheter 100(FIG. 1) to control a movable electrode 146 a that is disposed along adistal end of the tip assembly 1100. In the illustrated tip assembly,the distal end of the tip assembly 1100 is curved in an arcuate mannerand the arcuate curve is oriented in a plane that is substantiallyperpendicular to a longitudinal axis of the shaft 110, such as describedin the above referenced PCT application. The approximate ninety degreebend 1110 in the tip assembly may be an active bend or a fixed bend.

As shown in FIG. 11, the distal end of the tip assembly 1100 may includea movable electrode 146 a that is movable between a first position and asecond position spaced apart along a length of the distal end of the tipassembly 140. In the embodiment illustrated, the movable electrode 146 aslides along a length of the distal end that spans approximately 360degrees, and when used for ablation, may be used to form a circularlesion. The radius of curvature of the arcuate curve may be adjustable,as described in the aforementioned PCT application. The very distal endof the tip assembly 1100 may include a cap electrode 146 b, oralternatively, the cap may be made from a non-conductive material andmay simply serve to terminate the very distal end of the tip assembly1100. Where a cap electrode 146 b is used, an insulating spacer may beplaced proximally of the cap electrode to prevent the movable electrode146 a from electrically contacting the cap electrode 146 b.

As shown in FIG. 12, which is a cross sectional side view of the distalend of the tip assembly in FIG. 11 taken along line 12-12, the electrode146 a may be attached to a cylindrically-shaped plastic slider 1210 thatthat can slide back and forth along a length of the distal end of thetip assembly 1110. In the embodiment shown, the distal end of a metalpush/pull cable 1220 is welded to an outer surface of the electrode 146a, with the proximal end of the push/pull 1220 cable being attached toan actuator 122, 124 on the handle 120. For example, the push/pull cable1220 may be attached to the slider 234 as illustrated in FIGS. 2-4, oralternatively, the push/pull cable 1220 may be attached to the thumbwheel 122 as illustrated in FIGS. 5-6. The push/pull cable 1220 may bedisposed within a central lumen 1230 in the shaft 110 of the catheterfrom the proximal end of the shaft 110 to the tip assembly 1110, whereinit then passes through an outer lumen 1240 of the tip assembly 1110. Thedistal end of the push/pull cable 1220 emanates through a slit 1250 inthe tip assembly 1110. It should be appreciated that in embodimentswhere it is desired that the push/pull cable 1220 not be electricallyconnected to the electrode, the push/pull cable 1220 may be attached tothe plastic slider 1210, rather than to the electrode 146 a. It shouldalso be appreciated that the push/pull wire 1220 need not be made frommetal, as non-conducting materials may also be used, as known to thoseskilled in the art.

FIG. 13 is a cross sectional erid view of distal end of the tip assembly1110 illustrated in FIG. 12, taken along line 13-13. FIG. 13 illustratesthe slit 1250 in the distal end of the tip assembly 1110 through whichthe push/pull cable 1220 protrudes. The tip assembly 1110 may include anumber of other lumens 1310 that may be used to hold other cables toprovide steering of the tip assembly, etc. Further details of thesliding electrode described with respect to FIGS. 11-13 are provided incommonly assigned U.S. Pat. No. 6,245,066, which is incorporated hereinby reference in its entirety.

FIGS. 14 and 15 illustrate a catheter in which the distal end of thecatheter shaft 110 includes a braided conductive mesh 1410 that may beexpanded (deployed) and collapsed (un-deployed) radially about thedistal end of the catheter. As illustrated, the distal end of thecatheter includes a first collar 1420 that is used to secure a proximalend of the conductive mesh 1410 in a fixed position around thecircumference of the shaft 110, and a second and movable collar 1430that is used to secure the distal end of the conductive mesh 1410 aroundthe circumference of the shaft 110. The second collar 1430 may be movedproximally and distally along the distal end of the shaft 110 throughthe use of a cable, for example cable 230 (FIGS. 2-4) attached to anactuator 122, 124 on the handle 120. For example, where the distal endof the cable 230 is attached to the second collar 1430 and the proximalend of the cable 230 is attached to the slide actuator 124, movement ofthe slide actuator 124 in a proximal direction causes the second collarto move proximally along the shaft and causes the braided conductivemesh 140 to expand in a radial direction, as illustrated in FIG. 14, andin phantom in FIG. 15. Movement of the slide actuator 124 in a distaldirection results in collapsing of the braided conductive mesh 1410. Itshould be appreciated that the operation of the first and second collarsmay be reversed, such that the first collar 1420 is movable and thesecond collar 1430 is fixed in position. The distal tip portion of thecatheter shaft 110 may include a cap 1440, which may be made from anelectrically insulating material, or an electrically conductivematerial, such that the cap 1440 may be used as an electrode.

FIG. 16 illustrates another handle that may be used with embodiments ofthe present invention. In the embodiment depicted in FIG. 16, the handle120 includes three actuators 122, 124, and 124 a. For example, thehandle may include a thumb wheel actuator 122, and two slide actuators124, 124 a. One or more of these actuators may be used to operate acable attached thereto in both tension and compression, for controllingoperation of the catheter. For example, the thumb wheel actuator 122 maybe used to change the orientation of the distal end of the catheterrelative to the longitudinal axis of the shaft 110 in one or twodifferent directions. The first slide actuator 124 may be used toincrease and/or decrease the radius of curvature of an arcuately curveddistal end of a tip assembly attached to the distal end of the catheter,and the second slide actuator 124 a may be used to control theorientation of the of the tip assembly relative to the longitudinal axisof the shaft 110 of the catheter 100 in one or two different directionof movement that are orthogonal to the directions provided by use of thethumb wheel actuator 122. Alternatively, the second slide actuator 124Amay be used to move a sliding electrode proximally and distally alongthe distal end of the tip assembly. Alternatively still, the thumbwheelactuator 122 or the first slide actuator 124 may be used for changingthe orientation of the tip assembly or the radius of curvature of thedistal end in a first direction, and the second slide actuator 124 a maybe used for changing the orientation of the tip assembly or the radiusof curvature in the opposite direction. Alternatively still, the firstslide actuator 124 may be used for controlling an active bend (see FIG.21), the thumbwheel actuator 122 may be used for changing the radius ofcurvature of the distal end of the tip assembly, and the second slideactuator 124 a may be used for changing the orientation of the tipassembly in a first and/or second direction (e.g., for steering of theproximal end of the tip assembly.)

Having thus described at least one illustrative embodiment of theinvention, various alterations, modifications, and improvements willreadily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to be within the spirit andscope of the invention. Accordingly, the foregoing description is by wayof example only and is not intended as limiting. The invention islimited only as defined in the following claims and the equivalentsthereto.

1. A catheter comprising: a handle comprising: a housing having aproximal end, a distal end, and a longitudinal axis that extends fromthe proximal end of the housing to the distal end of the housing; acable, disposed in the housing, that extends through the proximal end ofthe housing, a portion of the cable that is disposed in the housingbeing movable, under compression, in a first direction that issubstantially aligned with the longitudinal axis of the housing; and aguide, disposed in the housing, adapted to prevent the portion of thecable from moving in a second direction that is transverse to the firstdirection when the portion of the cable is moved in the first direction;and an elongated shaft, a proximal end of the elongated shaft beingattached to the distal end of the housing, wherein the cable extendsthrough the distal end of the housing and into the elongated shaft;wherein a distal end of the elongated shaft is coupled to a conductivebraided mesh; and wherein a distal end of the cable is coupled to adistal end of the braided mesh, and wherein the distal end of thebraided mesh is movable distally in response to movement of the portionof the cable in the first direction.
 2. The catheter of claim 1, whereinthe guide includes: a hollow mandrel formed from a material that isstiffer, in compression, than the cable, the cable being disposed withinthe mandrel; and a retainer, attached to the housing and the mandrel, toretain the mandrel in a fixed position within the housing.
 3. Thecatheter of claim 2, wherein the mandrel is cylindrically shaped.
 4. Thecatheter of claim 2, wherein the mandrel has a length that isapproximately twenty percent of a length of the portion of the cable. 5.The catheter of claim 1, wherein the guide is separate from the housingand removably attached thereto.
 6. The catheter of claim 1, wherein thecable is approximately 0.011 inches in diameter.
 7. The catheter ofclaim 1, wherein the catheter is an electrophysiology catheter.
 8. Thecatheter of claim 1, wherein the portion of the cable that is disposedin the housing is movable, under compression, proximally relative to thehousing in the first direction.
 9. The catheter of claim 1, wherein theportion of the cable that is disposed in the housing is movable, undercompression, distally relative to the housing in the first direction.10. The catheter of claim 9, wherein the portion of the cable that isdisposed in the housing is movable, under tension, proximally relativeto the housing in a third direction that is opposite the firstdirection.
 11. The catheter of claim 1, wherein the elongated shaft hasa diameter of approximately 6 French.
 12. The catheter of claim 1,wherein a distal end of the cable is attached to a distal end of theelongated shaft, and wherein the distal end of the elongated shaft ismovable relative to a proximal end of the elongated shaft in response tomovement of the portion of the cable in the first direction.
 13. Thecatheter of claim 1, wherein the catheter for use with the handlecomprises an elongate shaft, and wherein the guide is separate from theelongated shaft.
 14. The catheter of claim 1, wherein the guide includesa mandrel having a through-hole occupied by a portion of the cable,wherein the through-hole is sized and shaped to prevent the portion ofthe cable occupying the through-hole from moving in any directiontransverse to the first direction.
 15. The catheter of claim 14, whereinthe through-hole has a diameter that is 25 to 50 percent greater than anouter diameter of the cable.
 16. The handle catheter of claim 14,wherein the through-hole has a diameter that is 10 to 20 percent greaterthan an outer diameter of the cable.
 17. A catheter comprising: a handlecomprising: a housing having a proximal end, a distal end, and alongitudinal axis that extends from the proximal end of the housing tothe distal end of the housing; a cable, disposed in the housing, thatextends through the proximal end of the housing, a portion of the cablethat is disposed in the housing being movable, under compression, in afirst direction that is substantially aligned with the longitudinal axisof the housing; and a guide, disposed in the housing, adapted to preventthe portion of the cable from moving in a second direction that istransverse to the first direction when the portion of the cable is movedin the first direction; and an elongated shaft, a proximal end of theelongated shaft being attached to the distal end of the housing, whereinthe cable extends through the distal end of the housing and into theelongated shaft; wherein a distal end of the elongated shaft includes atleast one electrode; and wherein a distal end of the cable is attachedto the at least one electrode, and wherein the at least one electrode ismovable distally along the distal end of the elongated shaft in responseto movement of the portion of the cable in the first direction.
 18. Thecatheter of claim 17, wherein a distal end of the elongated shaftincludes a tip assembly has an arcuate curve, wherein a distal end ofthe cable is attached to a distal end of the tip assembly, and wherein aradius of curvature of the arcuate curve is adjustable in response tomovement of the portion of the cable in the first direction.
 19. Acatheter comprising: a handle comprising: a housing having a proximalend, a distal end, and a longitudinal axis that extends from theproximal end of the housing to the distal end of the housing; a cable,disposed in the housing, that extends through the proximal end of thehousing, a portion of the cable that is disposed in the housing beingmovable, under compression, in a first direction that is substantiallyaligned with the longitudinal axis of the housing; and a guide, disposedin the housing, adapted to prevent the portion of the cable from movingin a second direction that is transverse to the first direction when theportion of the cable is moved in the first direction; and an elongatedshaft, a proximal end of the elongated shaft being attached to thedistal end of the housing, wherein the cable extends through the distalend of the housing and into the elongated shaft; wherein a distal end ofthe elongated shaft is coupled to a conductive braided mesh; and whereina distal end of the cable is attached to a proximal end of the braidedmesh, and wherein the proximal end of the braided mesh is movabledistally along the distal end of the elongated shaft in response tomovement of the portion of the cable in the first direction.
 20. Acatheter comprising: a handle comprising: a housing having a proximalend, a distal end, and a longitudinal axis that extends from theproximal end of the housing to the distal end of the housing; a cable,disposed in the housing, that extends through the proximal end of thehousing, a portion of the cable that is disposed in the housing beingmovable, under compression, in a first direction that is substantiallyaligned with the longitudinal axis of the housing; and means forpreventing the portion of the cable from moving in a second directionthat is transverse to the first direction when the portion of the cableis moved in the first direction; wherein the portion of the cable thatis disposed in the housing is movable, under compression, distallyrelative to the housing in the first direction; and an elongated shaft,a proximal end of the elongated shaft being attached to the distal endof the housing, wherein the cable extends through the distal end of thehousing and into the elongated shaft; wherein a distal end of theelongated shaft is coupled to a conductive braided mesh, wherein adistal end of the cable is attached to one of a distal end and aproximal end of the braided mesh, and wherein the one of the distal endand the proximal end of the braided mesh is movable distally in responseto movement of the portion of the cable in the first direction.
 21. Thecatheter of claim 20, wherein the means for preventing includes: ahollow mandrel formed from a material that is stiffer, in compression,than the cable, the cable being disposed within the mandrel; and meansfor retaining the mandrel in a fixed position within the housing. 22.The catheter of claim 21, wherein the mandrel is cylindrically shaped.23. The catheter of claim 21, wherein the mandrel has a length that isapproximately twenty percent of a length of the portion of the cable.24. The catheter of claim 20, wherein the means for preventing isremovably attached within the housing.
 25. The catheter of claim 20,wherein the catheter is an electrophysiology catheter.
 26. The catheterof claim 20, wherein the portion of the cable that is disposed in thehousing is movable, under compression, distally relative to the housingin the first direction.
 27. The catheter of claim 26, wherein theportion of the cable that is disposed in the housing is movable, undertension, proximally relative to the housing in a third direction that isopposite the first direction.
 28. The catheter of claim 26, wherein thecatheter further comprises an elongated shaft, a proximal end of theelongated shaft being attached to the distal end of the housing, andwherein the cable extends through the distal end of the housing and intothe elongated shaft.
 29. The catheter of claim 28, wherein the elongatedshaft has a diameter of approximately 6 French, and wherein the cable isapproximately 0.011 inches in diameter.
 30. The catheter of claim 20,wherein a distal end of the cable is attached to a distal end of theelongated shaft, and wherein the distal end of the elongated shaft ismovable relative to a proximal end of the elongated shaft in response tomovement of the portion of the cable in the first direction.
 31. Thecatheter of claim 20, wherein the handle further comprises: actuatormeans, attached to the housing, for applying a compressive force to theportion of the cable to move the portion of the cable in the firstdirection in response to movement of the actuator means.
 32. Thecatheter of claim 20, wherein the means for preventing is separate fromthe elongated shaft.
 33. A catheter comprising: a handle comprising: ahousing having a proximal end, a distal end, and a longitudinal axisthat extends from the proximal end of the housing to the distal end ofthe housing; a cable, disposed in the housing, that extends through theproximal end of the housing, a portion of the cable that is disposed inthe housing being movable, under compression, in a first direction thatis substantially aligned with the longitudinal axis of the housing; andmeans for preventing the portion of the cable from moving in a seconddirection that is transverse to the first direction when the portion ofthe cable is moved in the first direction; wherein the portion of thecable that is disposed in the housing is movable, under compression,distally relative to the housing in the first direction; and anelongated shaft, a proximal end of the elongated shaft being attached tothe distal end of the housing, wherein the cable extends through thedistal end of the housing and into the elongated shaft; wherein a distalend of the elongated shaft includes at least one electrode, wherein adistal end of the cable is attached to the at least one electrode, andwherein the at least one electrode is movable distally along the distalend of the elongated shaft in response to movement of the portion of thecable in the first direction.
 34. The catheter of claim 33, wherein adistal end of the elongated shaft includes a tip assembly has an arcuatecurve, wherein a distal end of the cable is attached to a distal end ofthe tip assembly, and wherein a radius of curvature of the arcuate curveis adjustable in response to movement of the portion of the cable in thefirst direction.
 35. A method of using a catheter having a handle, thehandle having walls defining a cavity, a proximal end, a distal end, anda longitudinal axis that extends from the proximal end of the handle tothe distal end of the handle, the method comprising acts of: applying acompressive force to a portion of a cable that is disposed in the cavityto move the portion of the cable in a first direction that issubstantially aligned with the longitudinal axis of the handle; andwithin the cavity, constraining the portion of the cable such that theportion of the cable is prevented from moving in a second direction thatis transverse to the first direction in response to the act of applying;wherein the catheter includes an elongated shaft having a proximal endthat is attached to the distal end of the handle, wherein the cableextends through the distal end of the handle and into the elongatedshaft, wherein a distal end of the elongated shaft is coupled to aconductive braided mesh, and wherein a distal end of the cable isattached to one of a distal end and a proximal end of the braided mesh,the method further comprising an act of moving the one of the distal endand the proximal end of the braided mesh distally in response tomovement of the portion of the cable in the first direction.
 36. Themethod of claim 35, further comprising an act of: applying a rotationalforce to an actuator that is disposed on the handle and attached to theportion of the cable to apply the compressive force to the portion ofthe cable.
 37. The method of claim 35, further comprising an act of:applying a linear force to an actuator that is disposed on the handleand attached to the portion of the cable to apply the compressive forceto the portion of the cable.
 38. The method of claim 35, wherein thecatheter includes an elongated shaft having a proximal end that isattached to the distal end of the handle, wherein the cable extendsthrough the distal end of the handle and into the elongated shaft, andwherein a distal end of the cable is attached to a distal end of theelongated shaft, the method further comprising an act of moving thedistal end of the elongated shaft relative to the proximal end of theelongated shaft in response to movement of the portion of the cable inthe first direction.
 39. The method of claim 35, wherein the act ofconstraining comprises constraining the portion of the cable with amandrel having a through-hole occupied by a portion of the cable,wherein the through-hole is sized and shaped to prevent the portion ofthe cable occupying the through-hole from moving in any directiontransverse to the first direction.
 40. The method of claim 39, whereinthe through-hole has a diameter that is 25 to 50 percent greater than anouter diameter of the cable.
 41. The method of claim 39, wherein thethrough-hole has a diameter that is 10 to 20 percent greater than anouter diameter of the cable.
 42. A method of using a catheter having ahandle, the handle having walls defining a cavity, a proximal end, adistal end, and a longitudinal axis that extends from the proximal endof the handle to the distal end of the handle, the method comprisingacts of: applying a compressive force to a portion of a cable that isdisposed in the cavity to move the portion of the cable in a firstdirection that is substantially aligned with the longitudinal axis ofthe handle; and within the cavity, constraining the portion of the cablesuch that the portion of the cable is prevented from moving in a seconddirection that is transverse to the first direction in response to theact of applying; wherein the catheter includes an elongated shaft havinga proximal end that is attached to the distal end of the handle, whereinthe cable extends through the distal end of the handle and into theelongated shaft, and wherein a distal end of the elongated shaftincludes at least one electrode that is movably attached to a distal endof the cable, the method further comprising an act of moving the atleast one electrode distally along the distal end of the elongated shaftin response to movement of the portion of the cable in the firstdirection.
 43. The method of claim 42, wherein the catheter includes anelongated shaft having a proximal end that is attached to the distal endof the handle, wherein the cable extends through the distal end of thehandle and into the elongated shaft, wherein a distal end of theelongated shaft includes a tip assembly having an arcuate curve, andwherein a distal end of the cable is attached to a distal end of the tipassembly, the method further comprising an act of adjusting a radius ofcurvature of the arcuate curve in response to movement of the portion ofthe cable in the first direction.
 44. A catheter comprising: anelongated shaft; and a handle comprising: a housing having a proximalend and a distal end, the distal end of the housing being attached to aproximal end of the elongated shaft; a cable, disposed in the housing,that extends through the distal end of the housing and into theelongated shaft; an actuator, attached to the housing and the cable, theactuator being movable between a first position in which the cableextends a first distance into the elongated shaft and a second positionin which the cable extends a second distance into the elongated shaft,the second distance being less than the first distance; and a guide,disposed in the housing and separate from the elongated shaft, adaptedto maintain a portion of the cable that is disposed between the distalend of the housing and the actuator when the actuator is in the secondposition in a substantially fixed lateral position when the actuator ismoved toward the first position; wherein a distal end of the elongatedshaft is coupled to a conductive braided mesh; and wherein a distal endof the cable is coupled to a distal end of the braided mesh, and whereinthe distal end of the conductive braided mesh is movable proximally anddistally in response to movement of the actuator.
 45. The catheter ofclaim 44, wherein the guide includes: a hollow mandrel formed from amaterial that is stiffer, in compression, than the cable, the cablebeing disposed within the mandrel; and a retainer, attached to thehousing and the mandrel, to retain the mandrel in a fixed positionwithin the housing.
 46. The catheter of claim 45, wherein the mandrel iscylindrically shaped.
 47. The catheter of claim 45, wherein the mandrelhas a length that is approximately twenty percent of a length of theportion of the cable that is disposed between the distal end of theelongated shaft and the actuator when the actuator is in the secondposition.
 48. The catheter of claim 46, wherein the housing has alongitudinal axis that is aligned with the proximal end of the elongatedshaft, and wherein the actuator is a slide actuator that is movablealong the longitudinal axis of the housing.
 49. The catheter of claim48, wherein the substantially fixed lateral position is aligned with thelongitudinal axis of the housing.
 50. The catheter of claim 44, whereinthe guide is separate from the housing and removably attached thereto.51. The catheter of claim 44, wherein the guide is further adapted tomaintain the portion of the cable that is disposed between the distalend of the housing and the actuator when the actuator is in the secondposition in the substantially fixed lateral position when the actuatoris moved toward the second position.
 52. The catheter of claim 44,wherein the actuator is a thumb wheel actuator.
 53. The catheter ofclaim 44, wherein the cable is movable distally with respect to thehousing in compression, and proximally with respect to the housing intension.
 54. The catheter of claim 44, wherein the cable isapproximately 0.011 inches in diameter.
 55. The catheter of claim 44,wherein the elongated shaft has a diameter of approximately 6 French.56. The catheter of claim 44, wherein the catheter is anelectrophysiology catheter.
 57. The catheter of claim 44, wherein adistal end of the cable is attached to a distal end of the elongatedshaft, and wherein the distal end of the elongated shaft is movablerelative to a proximal end of the elongated shaft in response tomovement of the actuator.
 58. The catheter of claim 44, wherein theguide includes a mandrel having a through-hole occupied by a portion ofthe cable, and wherein the through-hole has a diameter that is 25 to 50percent greater than an outer diameter of the cable.
 59. The catheter ofclaim 44, wherein the guide includes a mandrel having a through-holeoccupied by a portion of the cable, and wherein the through-hole has adiameter that is 10 to 20 percent greater than an outer diameter of thecable.
 60. A handle for use with a catheter having an elongated shaft,the handle comprising: a housing having a proximal end and a distal end,the distal end of the housing being attached to a proximal end of theelongated shaft; a cable, disposed in the housing, that extends throughthe distal end of the housing and into the elongated shaft; an actuator,attached to the housing and the cable, the actuator being movablebetween a first position in which the cable extends a first distanceinto the elongated shaft and a second position in which the cableextends a second distance into the elongated shaft, the second distancebeing less than the first distance; and a guide, disposed in the housingand separate from the elongated shaft, adapted to maintain a portion ofthe cable that is disposed between the distal end of the housing and theactuator when the actuator is in the second position in a substantiallyfixed lateral position when the actuator is moved toward the firstposition; wherein the actuator is a thumb wheel actuator; and whereinthe thumb wheel includes an arcuate wall, disposed on a proximal portionof the thumb wheel actuator, that prevents the cable from bowing in alateral direction as the thumb wheel is rotated toward the firstposition.
 61. The handle of claim 60, wherein the arcuate wall spansless than one hundred and eighty degrees.
 62. A catheter comprising: anelongated shaft; and a handle, the handle comprising: a housing having aproximal end and a distal end, the distal end of the housing beingattached to a proximal end of the elongated shaft; a cable, disposed inthe housing, that extends through the distal end of the housing and intothe elongated shaft; an actuator, attached to the housing and the cable,the actuator being movable between a first position in which the cableextends a first distance into the elongated shaft and a second positionin which the cable extends a second distance into the elongated shaft,the second distance being less than the first distance; and a guide,disposed in the housing and separate from the elongated shaft, adaptedto maintain a portion of the cable that is disposed between the distalend of the housing and the actuator when the actuator is in the secondposition in a substantially fixed lateral position when the actuator ismoved toward the first position; wherein a distal end of the elongatedshaft includes at least one electrode; and wherein a distal end of thecable is attached to the at least one electrode, and wherein the atleast one electrode is movable proximally and distally along the distalend of the elongated shaft in response to movement of the actuator. 63.The catheter of claim 62, wherein a distal end of the elongated shaftincludes a tip assembly has an arcuate curve, wherein a distal end ofthe cable is attached to a distal end of the tip assembly, and wherein aradius of curvature of the arcuate curve is adjustable in response tomovement of the actuator.
 64. A handle for use with a catheter having anelongated shaft, the handle comprising: a housing having a proximal endand a distal end, the distal end of the housing being attached to aproximal end of the elongated shaft; a cable, disposed in the housing,that extends through the distal end of the housing and into theelongated shaft; an actuator, attached to the housing and the cable, theactuator being movable between a first position in which the cableextends a first distance into the elongated shaft and a second positionin which the cable extends a second distance into the elongated shaft,the second distance being less than the first distance; and a guide,disposed in the housing and separate from the elongated shaft, adaptedto maintain a portion of the cable that is disposed between the distalend of the housing and the actuator when the actuator is in the secondposition in a substantially fixed lateral position when the actuator ismoved toward the first position; wherein the cable is a first cable, theactuator is a first actuator, the guide is a first guide, and whereinthe substantially fixed lateral position is a first substantially fixedlateral position, the handle further comprising: a second cable,disposed in the housing, that extends through the distal end of thehousing and into the elongated shaft; a second actuator, attached to thehousing and the second cable, the second actuator being movable betweena third position in which the second cable extends a third distance intothe elongated shaft and a fourth position in which the second cableextends a fourth distance into the elongated shaft, the fourth distancebeing less than the second distance; and a second guide, disposed in thehousing, adapted to maintain a portion of the second cable that isdisposed between the distal end of the housing and the second actuatorwhen the second actuator is in the fourth position in a secondsubstantially fixed lateral position when the second actuator is movedtoward the third position.
 65. The handle of claim 64, wherein thesecond cable is movable distally with respect to the housing incompression, and proximally with respect to the housing in tension.